Astacus or Astakos (Ancient Greek:Ἄστακος) was a town on the west coast of ancient Acarnania, on a bay, one side of which is formed by the promontory anciently named Crithote. Astacus is said to have been a colony of Cephallenia. At the commencement of the Peloponnesian War, it was governed by a tyrant, named Evarchus, who was deposed by the Athenians in 431BCE, but was shortly afterwards restored by the Corinthians. It is mentioned as one of the towns of Acarnania in a Greek inscription, the date of which is subsequent to 219BCE.

Its site is located near the modern Astakos.

This articleincorporates text from a publication now in thepublic domain:Smith, William, ed. (1854–1857). "Astacus". Dictionary of Greek and Roman Geography. London: John Murray.

38°33′17″N 21°05′29″E/38.5546°N 21.0915°E/ 38.5546; 21.0915